What do you mean when the Los light of set-top box is flashing red light? It may be caused by the fracture of optical fiber, and the optical fiber is relatively fragile. Do not bend it in daily use. It may also be that the network cable is not plugged in properly. You can pull out the plug and then plug it in again. Or if the set-top box fails, you need to contact the operator to solve the problem.
机顶盒 los 亮红灯，可能是光纤断裂导致，光纤比较脆弱，日常使用中不要弯折。也可能是网线没有插好，可以将插头拔下，然后重新插入。或是机顶盒出现故障，需要联系运营商解决。
The red light of the set-top box Los may be caused by the broken optical fiber. The optical fiber is relatively fragile. Do not bend it in daily use. It may also be that the network cable is not plugged in properly. You can pull out the plug and then plug it in again. Or if the set-top box fails, you need to contact the operator to solve the problem.
los 亮红灯，代表光纤猫接收不到信号，不能上网，可以关闭所有路由器过个 20 分钟左右再开启查看。这种故障用户无法自行维修，需要专门的人员和光纤工具，建议致电网络运营商报修。
The red light of Los indicates that the fiber-optic cat can not receive the signal and cannot access the Internet. You can turn off all routers and turn it on again after about 20 minutes. This kind of fault can not be repaired by users themselves, and special personnel and optical fiber tools are required. It is recommended to call the network operator for repair.
宽带 los 闪红灯，学名错误 651，是宽带上网错误代码查询障碍的现象之一，具体表现是网卡灯不亮或一直闪。出现 651 错误提示一般是由于用户终端电脑与网通局端设备连接不通所导致的。
Broadband Los flashing red light, scientific name error 651, is one of the phenomena of broadband Internet access error code query obstacles, specific performance is the network card light is not on or always flashing. The 651 error prompt is usually caused by the connection between the user terminal computer and the office equipment of Netcom.
光猫指示灯的正常状态应该是：power（电源灯）常亮；PON 灯常亮；LOS 灯不亮；LAN 口对应插上网线的接口，指示灯常亮或闪烁。
The normal state of the light cat indicator should be: power is always on; PON is always on; Los is not on; the indicator light is always on or flashing when the LAN port is connected to the Internet line.
Precautions for use of set top box:
1、一般机顶盒的重置键在机身背面，如果出现系统故障，可以进行重置，建议用户不要私自按下重置 键，可以在维修人员的协助下进行操作，因为机顶盒内部有配置数据，按下 reset 可能导致数据丢失。
1. Generally, the reset key of set-top box is located on the back of the body. In case of system failure, it can be reset. It is recommended that the user should not press the reset key privately, but can operate with the assistance of maintenance personnel, because there is configuration data inside the set-top box, pressing reset may cause data loss.
2. Do not put the set-top box in direct sunlight, which may cause deformation of the shell and affect the service life of the equipment.